I bought a preformed stainless fuel line and tried to cut off the hose end and flare it for an AN fitting. That stuff is rock hard! I can't even get the clamp to grab the tube, it just pushes back out. If I did flare it, I'm guessing it would crack.

So I went online to find annealing methods for SS. I found something that, in general describes three different processes but not a "how too". Anyone done this?

Pardon ME, but over the decades I have replaced BRAKE lines with a much higher line pressures, to the rear and front and never used stainless or anything that tough and UNworkable....as in WHY BOTHER???

just cause you CAN?? shit, my rear brakes on the vette had the OEM line blow some years ago....bought two ~5" lengths of brake line, and a inline coupling, and so had to cut to length, double flare the end and it's still in use today, same as many another car over the years....

stainless?? WHY?? show car?? what racing body demands that??

I fail to see the need for the aggravation.....

__________________
"Hell, there are no rules here ... we're trying to accomplish something." Thomas Edison
I have a little list, let ALL of them be MIST......

Larry, did you buy stailess line for brakes? That usually come as annealed tubing. I would not try heating it and experiment with it because well...brakes are kind of important LOL

Even double flaring annealed is a PITA and it probably will crack. A solution will be to make sure it's seamless tubing and then use a 37deg. flare tool so you have an increased sealing surace and a seperate flare sleeve and nut. This will allow you to use a single flare instead.

I agree with the article you posted, put it in your forming tool (hopefully it's not a hydraulic one), heat the tube to orange (1080 degrees), then flare and let it cool to air temperature naturally. It shouldn't take huge effort to form it. Once it's cooled, take a steel or brass brush and clean the scale off. Use scotch brite on the outside to make it shiny.

Do be careful to keep oil and stuff off your forming dies because that'll push impurities into the stainless.

Dot 3 brake fluid absorbs water and will start to rust out steel brake lines. When I removed the brake lines from my 68 Corvette, they were about 35 years old. The interior was lined with a reddish brown goo, which I'd say is rust. So stainless buys you rust resistance, especially on the interior where you can't see the rust beginning.
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For double flaring stainless steel lines, I've sent my lines off to a tubing company. I've used In-Line Tube in Michigan. I had them shorten and double flare stainless steel lines from the rear caliper to the trailing arm flex hose. The lines had to be shortened to fit the Stainless Steel Brake Corporation aluminum calipers.

Dot 3 brake fluid absorbs water and will start to rust out steel brake lines. When I removed the brake lines from my 68 Corvette, they were about 35 years old. The interior was lined with a reddish brown goo, which I'd say is rust. So stainless buys you rust resistance, especially on the interior where you can't see the rust beginning.
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For double flaring stainless steel lines, I've sent my lines off to a tubing company. I've used In-Line Tube in Michigan. I had them shorten and double flare stainless steel lines from the rear caliper to the trailing arm flex hose. The lines had to be shortened to fit the Stainless Steel Brake Corporation aluminum calipers.

some people think that brake fluid never needs to be changed.... not a good way to preserve long life and health IMO; but it's pretty common.

Dot 3 brake fluid absorbs water and will start to rust out steel brake lines. When I removed the brake lines from my 68 Corvette, they were about 35 years old. The interior was lined with a reddish brown goo, which I'd say is rust. So stainless buys you rust resistance, especially on the interior where you can't see the rust beginning.
...........................................
For double flaring stainless steel lines, I've sent my lines off to a tubing company. I've used In-Line Tube in Michigan. I had them shorten and double flare stainless steel lines from the rear caliper to the trailing arm flex hose. The lines had to be shortened to fit the Stainless Steel Brake Corporation aluminum calipers.

some people think that brake fluid never needs to be changed.... not a good way to preserve long life and health IMO; but it's pretty common.

OH, shoot, I forgot, I have used DOT 5 fluid for years now....in all my cars, my vette did pop the rear main line under the driver's door, but it's the only car to do that to me, DOT 5 of course will not rust....

and I hear many a dislike over it, and can't see/understand why....been in my '72 here for 18 years now....